Photosynthetic characteristics of two alpine flowers, Meconopsis integrifolia and Primula sinopurpurea

Meconopsis integrifolia and Primula sinopurpurea are ornamental plants native to high elevations in the Himalayas, thus cultivating them at lower altitudes poses challenges. In order to understand the physiological adaptability of M. integrifolia and P sinopurpurea to the different environments which are needed for the introduction and domestication of wild flowers, this study investigated their photosynthetic performance at lower altitudes in a nursery at an altitude of 3,260 m asl, and their photosynthetic responses to varying light and temperature conditions. On a clear day, the maximum photosynthetic rates in both species occurred at approx. 11:00 h, then decreased, indicating photo-inhibition at midday. Stomatal limitation played an important role in the depression of photosynthesis at midday. Although M. integrifolia had a lower light-saturated photosynthetic rate than P sinopurpurea, the daily mean photosynthetic rates of the two species were not significantly different. Photosynthesis in both alpine flowers was considerably sensitive to high temperature. The significant decreases in photosynthetic rates in P sinopurpurea and M. integrifolia at higher temperatures would limit their photosynthetic performance and growth at low altitudes.